Daylight is Family Time, especially for families with small or school aged children. Normally, work or school takes up a central block of daylight hours. Extensions of this central block, school activities, overtime at work, etc., can be said to "steal sunshine" from the rest of the daily schedule. There are numerous other aspects, teen driving limited to daylight hours, making the most out of harvest time daylight, etc..
Australians, I am told, have a name for this sort of thing: Work-Life Balance.
Mash-ups of daylight (or darkness) with daily scheduled activities require some extensive scientific calculations[1]. In the US, but not on data.gov AFAICT, the methods are the province of National Oceanic & Atmospheric Administration (NOAA). They provide a web page[2] useful for estimates, and (yearly) spreadsheets for analytical detail[3].
Daylight and duration of daylight varies with seasons of the year, which in turn is governed by latitude. There are several mapping aids available, e.g. [4].
When summing to approximate integrals, corrections for weekends, work weeks and National Holidays are necessary[5] as are corrections to Daylight Saving Time (Summer Time)[6]. The NOAA spreadsheets use an uncorrected local time.
In the US, hours worked are regulated, but not which hours are worked[7]. The regulations are silent on daylight or darkness hours. Industry groups may follow more complete standards[8].
With these resources, it ought to be possible to make an app/tool, available, for example, on data.gov which would enable a user to measure and visualize schedule changes as a proportion of daylight gained or lost. In the past, this visualization was too calculation intensive to be useful, but it is not by any stretch beyond the capabilities of current devices. I have prepared some simple graphical examples, which I will provide by request.
--Gannon
[1] http://www.srrb.noaa.gov/highlights/sunrise/solareqns.PDF
[2] http://www.srrb.noaa.gov/highlights/sunrise/sunrise.html
[3] http://www.esrl.noaa.gov/gmd/grad/solcalc/calcdetails.html
[4] http://www.findlatitudeandlongitude.com/
[5] US: http://www.opm.gov/operating_status_Schedules/fedhol/2010.asp
[6] Bibliography: http://www.srrb.noaa.gov/highlights/sunrise/sollinks.html#daylightsavingtime
[7] http://www.dol.gov/compliance/laws/comp-flsa.htm
[8] http://www.eicc.info/EICC%20CODE.htm